Peculiarities of Contemporary Surface Spore-Pollen Spectra from Southern Siberia (Tyva and Khakassia Republics)

Ecological Questions 26/2017: 49 –52 http://dx.doi.org/10.12775/EQ.2017.015

Peculiarities of contemporary surface spore-pollen spectra from southern Siberia (Tyva and Khakassia republics)

Tatiana Blyakharchuk

Institute for monitoring of climatic and ecological systems of Siberina branch of Russian Academy of Science (IMCES SB RAS). Russia. Tomsk. Akademicheski ave. 10/3, e-mail: [email protected] Received: 22 April 2017/Accepted: 31 May 2017

Abstract. In mountains and in intermountain depressions in the south of Western Siberia 31 contemporary (subrecent) spore-pollen spectra were collected with aim to reveal how adequate the composition of spore-pollen spectra reflects vegetation types in study area. It was found that pollen spectra from dry steppe of Tyva are characterized by dominance of Artemisia and Chenopodiaceae pollen, but more north located steppe of Khakassia – by abundance of Poaceae pollen among herbs and by considerable amount of tree pollen, mostly Betula and Pinus sylvestris. A high mountain spore-pollen spectra in Tyva are differed by dominance of Poaceae pollen and increased amount of Cyperaceae pollen with small amount of tree pollen. Spore-pollen spectra of mountain taiga are dominated by tree pollen of Pinus sibirica. Spectra with relic composition combining abundance of Artemisia pollen with increased amount of Picea and Larix pollen were found on the tops of Tannu-Ola ridge in south Tyva. The described features of modern spore-pollen spectra reflect real peculiarities of vegetation in places were these samples were collected including larch-spruce forest alternated with steppe parches on tops of Tannu-Ola ridge. Mathematical method of unconstrained cluster analysis fully conforms the grouping of modern pollen spectra according to vegetation types and hence supports the idea that spore-pollen spectra from mountain areas reflect accurately the vegetation types and composition of local plant communities.

Keywords: pollen, spores, subrecent pollen spectra, Siberia, vegetation.

1. Introduction cover. One of such regions – it is mountains of southern Siberia, for which very scarce data on subrecent spore- Investigation of surface (subrecent) spore-pollen spectra pollen data is published (Kunes et al. 2008). It is one of the is important for palaeogeographic research. On the base of rare regions on the Earth where natural vegetation cover subrecent pollen data can be reconstructed past vegetation survived. In spite of partial logging of mountain forests in cover and climate using palaeopollen data by method of the past, and attempts to plug steppe areas during Soviet biomisation (Prentice et al. 1996). Moreover the subrecent time the contemporary vegetation of this region is repre- pollen data together with modern climatic parameters in sented by natural plant successions depending on local and points of collected pollen spectra can be used for quanti- regional climates, altitude and types of soil. The purpose tative palaeoclimatic reconstructions by method of “best of our research consists in more detailed study of relation- modern analogues” applied to palaeopollen data (Over- ships between composition of modern spore-pollen spectra peck, Webb III & Prentice 1985; Guiot 1990; Nakagava and mother vegetation types, in order to get new knowl- et al. 2002). For such research the subrecent spore-pol- edge, which can be used during interpretation of palaeopollen data from regions are very important, especially for len data in this region. regions with diverse landscapes and complex vegetation 50 Tatiana Blyakharchuk

2. The study area parches of Artemisia steppe we met on the topes of Tannu- Ola Ridge in southern Tyva. On the contrary, real and dry steppe vegetation is spread on intermountain depressions, Khakasia and Tyva republics are located in the Altai-Sayan some of which, for example Tyva depression, are high el- mountain region 50º-55ºN, 85º-95ºE to the south of West evation steppe with height above sea level up to 900 m. Ac- Siberian Plain and Central Siberian Plateau, where cool cording to north-south climatic gradient a meadow steppe humid temperate-continental climate of Siberia meets with of north Khakasia changes to real Artemisa-grass steppe in arid sharp continental-climate of Central Asia. Vegetation south Khakasia and to dry and desert-steppe in the south of cover of study area reflects north-south climatic gradient Tyva republic on the boundary with Mongolia. as well as north-south decrease of precipitation and increase of continentality of climate. These gradients are su- perimposed on mountain relief, which causes formation of 3. Methods altitudinal belts of vegetation from steppe and dry steppe in intermountain depressions to mountain forests, sublap- In order to study modern spore-pollen spectra of all land- ine, alpine and tundra vegetation on mountain slopes and scape diversity in study region, we collected for pollen tops. The feature of southern Tyva vegetation – spreading analysis a series of 31 surface samples by method of moss of tundra-steppe vegetation on high altitudes and gradual polsters (Canňellas-Bolta et al. 2009) from different veg- decline of mountain forests belt due to increased aridity etation types and from different elevation in mountains and continentality of climate. Diversity of landscapes and and intermountain depressions of Tyva and Khakassia re- climates in study region promote to spreading of contrast publics. Detailed geobotanical descriptions of vegetation types of vegetation. Mountain forests composed by larch cover in sites of collecting of surface pollen spectra were (Larix sibirica Mill.), Siberian pine (Pinus sibirica Du performed. In places where mosses were absent (steppe Tour) and fir-tree (Abies sibirica Ledeb.) are spread on and desert vegetation) the surface detritus was collected. mountain depending on slope exposition and moisture In the laboratory samples were chemically treated by tra- availability. Birch (Betula pendula Roth.), spruce (Picea ditional alkaline and acetolisis methods with application of obovata Ledeb) and larch grow along river valleys and HF treatment in case of mineral contamination. All sam- birch and Scot’s pine (Pinus sylvestris L.) forests spread ples including detritus samples from desert-steppe con- on a piedmonts of the mountains. A relic type of veg- tained rich complex of well preserved pollen and spores. etation composed by spruce-larch forest alternated with During pollen analysis in general 300–600 palynomorphs

Figure 1. Contemporary surface spore-pollen spectra from Tyva and Khakasia republics Peculiarities of contemporary surface spore-pollen spectra from southern Siberia (Tyva and Khakassia republics) 51

were recognized and counted with use of light microscope This is interesting that surface pollen spectra of high under magnification 400 X. mountain areas of Tuva Republic differ by dominance of Poaceae pollen in combination with sedge pollen (Cyper- aceae) and pollen of dwarf birch (Betula nana). This is in 4. Results and discussions agreement with high mountain vegetation composition in Tyva. The other noticeable feature of high-mountain sur- Visual ranging of contemporary spore-pollen spectra ac- face pollen spectra of Tyva Republic – it is rather high cording to region, altitude and type of vegetation demon- amount of Pinus sibirica pollen, which can vary from 10.4 strates very well marked out groups of spectra (Fig. 1). to 22.3% (Fig. 1). The increased amount of Pinus sibirica These groups reflect following local types of vegetation pollen in these open treeless high mountain areas can be (from top of diagram to bottom): Tyva dry steppe; Tyva explained by long distant tree pollen brought to open tops high mountain steppe; Tannu-Ola spruce-larch mountain of mountains by winds from north located (in 200 km) forest; Khakassian meadow steppe; Sayan Mountain for- mountain forests of Altai Mountains. ests. Tannu-Ola Ridge from the south and from the north Pollen spectra of Tyva dry steppe differ from pollen is surrounded by steppe. Spruce-larch mountain forests spectra of Tyva high mountain steppe by dominance of with admixture of Siberian pine and patches of steppe Artemisia and Chenopodiaceae pollen. Something less vegetation spread on tops of Tannu-Ola mountain range. is amount of grass (Poaceae) pollen and in very small These mountains extend in latitudinal direction in the most amount presents tree pollen (Fig. 1). Among tree pol- south of Tyva Republic between Tyva steppe and Mongolia len only Pinus sibirica and Pinus sylvestris was found. steppe in Uvs-Nur hollow. As a result of this, pollen spec- Among mesophilous coniferous tree species only single tra from Tannu-Ola spruce-larch forest is rather specific. pollen grains of Picea obovata were found in separate It contains a lot of Artemisia pollen together with tree pol- samples and no one pollen grain of Abies sibirica. len of Pinus sibirica, Picea obovata and Larix (Fig. 1). The

Figure 2. Cluster tree of surface pollen spectra from Tyva and Khakassia republics built by unconstrained cluster analysis 52 Tatiana Blyakharchuk

increase of spruce pollen is not substantial and vary from pollen spectra, but it was more formal than visual group- 3.7 to 7.4%, but quite notable, because of not in steppe ing. As a result of this, pollen spectra of Khakassian steppe pollen spectra nor in high mountain pollen spectra we was classified as forested landscape and pollen spectra of don’t found such amount of spruce pollen. Actually this Tannu-Ola spruce-larch forest – as open landscape due to type of pollen spectra is very similar with pollen spectra strong influence of neighboring vegetation zones on forma- found in Glacial and Late Glacial sediments from Europe tion of pollen spectra. This says about need of caution in and Western Siberia. It is considered that this Late Gla- using of formal methods in estimation of contemporary and cial type of pollen spectra have no analogues in modern fossil spore-pollen spectra. All available meta data should vegetation on the Earth. It seems that on ridges of Tannu- be used during interpretation of pollen data. Only with use Ola Mountains in Tyva Republic still exists this relic type of it we can see that modern spore-pollen spectra from of vegetation wide spread in Eurasia during Glacial time. mountain areas of southern Siberia reflect appropriately In the pollen samples of north located Khakas- the existing vegetation types. sian meadow and grass steppe (more humid variant of steppe) dominate pollen of grasses (Poaceae) and in very small amount present Artemisia pollen. Pollen spectra Acknowledgements of Khakassian meadow steppe clearly differ also by increased amount of tree birch pollen (Betula pendula) and Research was performed with financial support of budget Scot’s pine (Pinus sylvestris). The last is caused by influ- theme of Institute of monitoring of climatic and ecologi- ence of north located birch forest-steppe of Western and cal systems SB RAS and grant № 17-55-52020/МНТ_а of Central Siberia and pine forests of mountain piedmonts. Russian Foundation of Basic Research. Sayan Mountains in the south are bounded by Tyva steppe and in the north – by south Khakassian steppe. But unlike to Tannu-Ola Ridge the Sayan mountain taiga References is much more vast and dense with humid local climate. As a result of this in pollen spectra of Sayan mountain Caňellas-Bolta N., Josep V.R. & Mercade V.A., 2009, forest predominate tree pollen of Pinus sibirica and Pinus Modern pollen-vegetation relationships along an alti- sylvestris, but pollen of Artemisia present in very small tudinal transect in the central Pyrenees (Southwestern amount. An amount of pollen of mesophilous coniferous Europe), The Holocene 19(8): 1185–1200. such as Abies sibirica and Picea obovata is also increased Guiot J., 1990, Methodology of the last climatic cycle re- reaching 2.2–8.4% and 0.3–1.8% respectively. construction from pollen data, Palaeogeography, Pal- Cluster analyses supports this grouping (Fig. 2). The aeoclimatology, Palaeoecology 80: 49–69. right branch of cluster tree (cluster 2) includes pollen spec- Kunes P., Pelankova B., Chytry M., Jankovska V., Pokorny tra of predominantly open landscapes (steppe and high P. & Petr L., 2008, Interpretation of the last-glacial veg- mountain vegetation), the left branch (cluster 1) – pre- etation of eastern-central Europe using modern ana- dominantly forest and forest-steppe pollen spectra. Cluster logues from southern Siberia, Journal of Biogeography 6 with serial numbers of spectra 1–7 marks pollen spectra 35: 2223–2236. of dry Tyva steppe. Pollen spectra of Tyva high mountain Nakagawa T., Tarasov P.E., Nishida K., Gotanda K. & steppe are grouped in neighboring cluster 7 with serial Yasuda Y., 2002, Quantitative pollen based climate re- numbers of samples 8–13 located in right corner of cluster construction in Japan: application to surface and late tree (Fig. 2). Cluster 5 of Tannu-Ola spruce-larch forest Quaternary spectra, Quaternary Science Reviews 21: pollen spectra also belongs to right branch of cluster tree 327–342. because of abundant Artemisia pollen. Cluster 4 of sur- Overpeck J.T., Webb T. III & Prentice L.C., 1985, Quan- face pollen spectra collected in mountain taiga of Western titative interpretation of fossil pollen spectra, dissimi- Sayan Mountains is very well allocated in left branch of larity coefficients and the method of modern analogs, cluster tree (serial numbers of samples 26–34). Three ad- Quaternary Research 23: 87–108. ditional samples from mountain taiga we used for cluster Prentice C., Guiot J., Huntley B., Jolly D. & Cheddadi analysis and they belong also to this cluster. Cluster 4 of R., 1996, Reconstructing biomes from palaeoecologi- pollen spectra collected in Khakassian meadow and grass cal data: a general method and its application to Euro- steppe is located in right corner of cluster tree. So group- pean pollen data at 0 and 6 ka, Climate Dynamics 12: ing of contemporary spore-pollen spectra from Khakasia 185–194. DOI: 10.1007/BF00211617 and Tyva by cluster analysis revealed the same types of